A Study To Evaluate the Efficacy and Safety Of Atezolizumab or Placebo in Combination With Neoadjuvant Doxorubicin + Cyclophosphamide Followed By Paclitaxel + Trastuzumab + Pertuzumab In Early Her2-Positive Breast Cancer

Clinical Study to Compare the Efficacy and to Evaluate the Safety and Immunogenicity of Trastuzumab Biosimilar HLX02 and EU-sourced Herceptin® in HER2-Positive, Locally Recurrent or Previously Untreated Metastatic Breast Cancer